In summary, it is found that: (i) three kinds of cardiac cells underwent phenotypic transformation, including CMs, ECs, and FBs; (ii) the expression of myosin subunits in cCM is abnormal, including the increased expression of MYH7, and decreased expression of MYH6, MYL4, MYL7; (iii) ECs have two specific disease-related phenotypes in HF, named inflammatory phenotype and muscularized phenotype; And (iv) Myo-FBs are increased in HF and are highly associated with cardiac fibrosis. This evidence concerns the gene MYL4 and hydrops fetalis.